Mounting arrangement

ABSTRACT

A web drive mounting arrangement is shown for isolating the web drive from shock and vibration and the stress caused thereby having a plate mounted within a main frame. A driving motor is mounted on the drive plate for driving a capstan which drives a web across a web contacting surface thereof. First and second spherical self-aligning bearings extend from the driving motor and are rotationally mounted upon the main frame. A third bearing is mounted between the plate and the main frame. The plane formed by the three bearings passes through the center of gravity of the web driving arrangement, while the third bearing mounts at the center of percussion of the web driving arrangement. This mounting arrangement thereby prevents vibrational forces parallel to the web contacting surface from causing deflections of that surface and causes vibrational forces perpendicular to the web contacting surface to produce a rotational motion about the first and second bearings attached to the driving motor.

United States Patent [7 2] Inventor Herbert F. Sanford Littleton, Colo.[21 Appl. No. 773,224 [22] Filed Nov. 4, 1968 [45] Patented Mar. 16,1971 [73] Assignee Honeywell Inc.

Minneapolis, Minn.

[54] MOUNTING ARRANGEMENT Primary Examiner-Richard A. SchacherAttorney-Arthur l-l. Swanson & Lockwood D. Burton ABSTRACT: A web drivemounting arrangement is shown for isolating the web drive from shock andvibration and the stress caused thereby having a-plate mounted within amain frame. A driving motor is mounted on the drive plate for driving acapstan which drives a web across a web contacting surface thereof.First and second spherical self-aligning bearings extend from thedriving motor and are rotationally mounted upon the main frame. A thirdbearing is mounted between the plate and the main frame. The planeformed by the three bearings passes through the center of gravity of theweb driving arrangement, while the third bearing mounts at the center ofpercussion of the web driving arrangement. This mounting arrangementthereby prevents vibrational forces parallel to the web contactingsurface from causing deflections of that surface and causes vibrationalforces perpendicular to the web contacting surface to produce arotational motion about the first and second bearings attached to thedriving motor.

SHEET 1 [IF 2 PATENTED NARI 6 l97| FORD INVENTOR. HER B ERT F.

ATTORNEY.

PATENTED m1 6 m1 sum 2 or 2 INVENTOR- HERBERT F. SANFORD 7 41 ATTORNEY.

MGIUNTKNG ARRANGEMENT The present invention relates to a mountingarrangement and, more particularly, to a mounting arrangement for awebdriving assembly wherein the assembly is mounted for preventing shockand vibration from disturbing the driving motion of the web and fromcreating stress within slidably mounting arrangement.

it is well-known known in the prior art to shock mount a drivingmechanism from the equipment driven thereby. Most of these arrangementsprevent vibrations from the driving mechanism from affecting the drivenequipment and are not concerned with preventing shock applied to theequipment from affecting the driving mechanism. The present invention isintended to be utilized within a webdriving arrangement wherein a web,such as magnetic tape, is driven at a precise predetermined rate ofspeed across a given area, such as an electromagnetic transducermounting area. Prior-art magnetic tape transports have utilized aseparate mounting plate for mounting the tape drive mechanism on themain frame of the tape transport. However, these mounting arrangementshave been substantially rigid and continue to transfer vibration fromthe driving mechanism to the frame and to transfer shock and vibrationfrom theframe to the driving mechanism. It has been found, for example,that a mounting plate may be precisely machined to within a thousandthof an inch, assembled, and mounted within the main frame of a magnetictape transport prior to final assembly checks. Shock and vibrationalforces acting on the main frame of the tape transport create stresseswithin the mounting plate which, in many cases,'actually'causemisalignment of the precisely machined plate during the'check out periodor during the early productive life of the tape transport. That is, theworking vibrations transferred from the main frame to the mounting platehave caused stress relief within the precisely machinedplate whichproduces dimensional changes therein. In the design of magnetic tapetransports, where precision and tolerance problems are a primeconcern,'the dimensional changes caused by stress relief can createsubstantial deterioration in the performance thereof.

Accordingly, it is an object of the present invention to provide amounting arrangement capable of isolating a driving assembly from shockand vibration and the stress created thereby.

Another object of the invention provides for a web drive mountingarrangement which prevents external shock and vibration from creatingstress distortions within a mounted web-driving assembly.

A further object of the present invention is to provide a web drivemounting arrangement which is capable of preventing external shock andvibration from affecting the driven web.

Still a further object of this invention provides a web drive mountingarrangement which mounts the web drive assembly whereby shock andvibration transmitted thereto are directed and concentrated into areasthat will not affect the driven web. I

in accomplishing these objects there has been provided mounting platemeans which is mounted within a main frame. Driving means'drive a webacross the mounting plate means; while first, second, and third mountingmeans are arranged for rotationally mounting the plate means within themain frame.

Other objects and many of the attendant advantages of the presentinvention will become readily apparent to those skilied in the art as abetter understanding thereof is obtained by reference to the followingdetailed description when considered in connection with the accompanyingdrawings, wherein:

MG. 1 is a front elevational view showing a web-driving assembly mountedon the main frame of a tape transport embodying the mounting arrangementof the present invention;

MG. 2 is a side elevation showing the web drive mounting arrangement ofthe present invention; and

H6. 3 is a rear view of FIG. 2.

Referring now to the drawings and particularly to FIG. 1, a magnetictape transport is shown generally at 10 having a main frame 12 which ismounted in a suitable electronic rack, not shown, by hinge members 14.Mounted on the main frame 12 are a supply and talreup reel 16 and 18,respectively. The supply and takeup reel, 16 and 18, are mounted on themain frame 12 of the magnetic tape transport by mounting hubs 20 whichattach to the shaft of a supply and takeup motor, not shown, mounted onthe back of the main frame 12. A web member, such as magnetic tape 22,unwinds from the supply reel 16 and passes over a suitable guide 2 5before wrapping around a tape cleaner 26. The tape then enters an edgeguiding arrangement 28 of a tape bin before wrapping l about a guideroller 30 and entering .a first vacuum bin 32. As tape exits the vacuumbin 32, it passes through an electromagnetic transducer mounting areaand wraps around a rubber coated capstan 34 before returning through thetransducer mounting area and entering a second vacuum bin 36. Electronictransducers, in the form of magnetic record/reproduce heads 38, areprovided in the transducer mounting areas between the first and secondvacuum bins, 3 2 and 56, and the capstan 34. After exiting the secondvacuum bin 36, the tape wraps 180 around a guide roller 40, passesthrough a second edge guide 28, over a second tape cleaner 42 and guide44, and winds upon the takeup reel 18.

As best seen in FIG. 2, the rubber coated capstan 34 is mounted upon theshaft 46 of a capstan drive motor 48. The capstan drive motor 48 may beone of several suitable motors, such as a DC torque motor having aprinted circuitrotor. Th'e capstan drive motor 48 and reel motors, notshown, are controlled from a control panel 50. Each vacuum bin acts toprovide a servocontrol for its related reel motor, as is well known inthe art. The capstan drive motor and vacuum bins are mounted on amounting plate 52 which forms the main support for a web drivingassembly 53, FIGS. 2 and 3. In turn, the web driving assembly 53 ismounted by the web mounting arrangement of the present invention withinthe main frame 12.

In the present embodiment, the mounting plate 52 is placed diagonallyacross the surface of the main frame 12. The ends of the mounting plate52 are therefore beveled at 45 to facilitate the mounting of the platewithin the main frame 12. The first and second vacuum bins 32 and 36 areformed as part of the web driving assembly 53. Each bin being formedfrom the mounting plate 52 which has a tape contacting surface 54 withsidewalls 56 extending upwardly therefrom. The

sidewalls 56 combine with a center wall 58 to mount an upper cover plate60-at a fixed, space relationship parallel tothe tape contacting surface54 of the mounting plate 52. The magnetic tape 22 is thus edge guidedbetween the tape contacting surface 54 and the parallel inner surface ofthe upper cover plate 60. The mounting plate 52 and the cover plate 60are extended outwardly in the areas between the tape cleaners 26 and 42and the guide rollers 30 and 44 for forming the edge guidingarrangements 28 referred to hereinabove. A vacuum port 62 is providedthrough the mounting plate 52 for supplying a vacuum to each of thevacuum bins, 32 and 36. The

vacuum port 62 is connected by a suitable vacuum hose 64 to a source ofreduced pressure, not shown.

As best seen in FIGS. 2 and 3, the web drive mounting arrangement formounting the web driving assembly 53 and its mounting plate 52 includesa pair of spherical self-aligning bearings 66 and 68 which mount onsuitable bosses 70 extending from opposite sides of the capstan drivemotor 48. The bearings include a toroidal member 72 having a sphericallyshaped outer surface which slidably engages a second toroidally shapedmember 74 having a spherically shaped inner surface. The secondtoroidally shaped member 74 may be constructed from an elastomericmaterial and is mounted within a U-shaped mounting frame 76, as bybonding. The toroidal member 72 thus forms a ball, while the secondtoroidal member forms a socket. This arrangement is known as a trunnionor gimbal bearing. A bolt 73 passes through the first toroidal member 72and threadably attaches to the capstan driven motor 48 at boss 70 forsecuring each bearing thereto. The Urshaped mounting frame 76 isattached to the main frame 12 by suitable means, such as welding. Thefirst and second bearing, 66 and 68, are arranged on opposite sides ofthe capstan drive motor 48 for forming a common axis perpendicular tothe longitudinal axis of the mounting plate 52 and parallel vto theplane thereof. A third bearing 80 is mounted on the back surface of themounting plate 52 opposite the tape contacting surface 54. This thirdbearing 80 is attached by a suitable bolt 78 to a point that is locatedalong the longitudinal axis of the web drive mounting arrangement.

As each bearing is free to rotate in all planes, movements within themain frame 12, caused by external shock and vibration, are preventedfrom being transmitted to the web driving assembly 53 through itsmounting plate 52. That is, the elastomeric toroidally shaped member 74serves to absorb shock and vibration while the rotational freedom of thetoroidal member 72 serves to further isolate the mounting plate 52 bypreventing vibrational motion from passing thereto.

The first, second, and third bearings 66, 68, and 80 are arranged in aplane which passes through the center of gravity of the web drivingassembly 53. Due to this arrangement, vibrational forces parallel to thetape contacting surface 54 are prevented from causing deflection of thatsurface. That is, forces acting parallel to the tape contacting surface54 create a resulting force which reacts about the center of gravity ofthe web driving assembly. The first, second, and third bearings thusproduce an equal and opposite resulting force which acts about the planein which they are located. There is no resulting bending moment withinthe mounting plate 52 as the center of gravity is located in the planecreated by the mounting points and the two forces react equally andoppositely against each other. This prevents the tape contacting surface54 from undergoing a deflection due to the vibrational forces parallelyacting thereon.

The third bearing 80 has been located on the center of percussion of theweb driving assembly. That is, the first and second bearings form acommon axis about which the mounting plate 52 can be rotated. The thirdbearing 80 is located at the point where an impulsive force appliedperpendicularly thereto produces no impulsive reaction force along thecommon axis formed by the first and second bearings, but produces only arotational force. Thus, vibrational forces applied perpendicularly tothe tape contacting surface 54 produce only rotational motion about thecommon axis formed by the first and second bearings, 66 and 68. Thisarrangement prevents the tape contacting surface 54 from undergoing asectional deflection or bending and tends to keep that surface flat andfree of deflections absorbing the forces which would otherwise causedeflection by undergoing a uniform rotational motion about the commonaxis. Therefore, vibrational forces acting on the mounting plate 52 andits tape contacting surface 54 have no effect on the tape being guidedthereacross as the surface is prevented from deflecting by the web drivemounting arrangement.

Thus, there has been provided a web drive mounting arrangement whichisolates the movements of a main frame from the web driving assembly 53and its mounting plate 52. Further, the mounting arrangement preventsvibrational forces from creating internal bending forces within themounting plate 52 for causing the sectional deflection of the tapecontacting surface thereof 54. This arrangement allows the magnetic tapeto be driven across the mounting plate free of the damaging effect ofshock and vibration.

Obviously, many modifications and variations of the present inventionwill become apparent to those skilled in the art; and, therefore, thepresent invention should be limited only by the appended claims.

lclaim:

1. A mounting arrangement for isolating a vibration sensitive assemblyfrom shock and vibration and the stress caused thereby, comprising:

a main frame;

a vibration sensitive assembly;

mounting plate means for supporting said vibration sensitive assembly;

first, second, and third mounting means each connected between said mainframe and said mounting plate means and arranged to allow a movement ofsaid mounting plate means in all planes with respect to said main frame;said first, second, and third mounting means each having one axis ofmovement arranged in a plane passing through the center of gravity ofthe combination of said mounting plate means and said vibrationsensitive assembly; and

whereby said vibration sensitive assembly is isolated from stresscreated by movements of said main frame.

2. A mounting arrangement as claimed in claim 1, wherein said mountingmeans include bearing means having a spherical portion attached to saidmounting plate means and a second spherical portion arranged to receivesaid first mentioned spherical portion attached to said main frame.

3. A mounting arrangement as claimed in claim 1, wherein:

said vibration sensitive means includes a web driving means and asurface parallel to a driven web; and

whereby vibrational forces parallel to said surface are prevented fromdeflecting said surface.

4. A mounting arrangement as claimed in claim 1, wherein:

said first and second mounting means attach to said mounting plate meansand extend oppositely therefrom along a common axis for attachmenttosaid main frame; said third mounting means attaches to said mountingplate means and extends therefrom perpendicularly to the common axisformed by the first and second mounting means at the center ofpercussion of the combination of said mounting plate means and saidvibration sensitive assembly for attachment to said main frame; saidvibration sensitive assembly includes a web driving means and a surfaceparallel to a driven web; and

whereby vibrational forces perpendicular to said surface produce arotational force about said common axis formed by said first and secondmounting means.

5. A mounting arrangement for isolating a web driving assembly fromshock and vibration and the stress caused thereby, comprising:

a main support frame;

mounting plate means having aweb contacting surface;

driving means mounted upon said mounting plate means and arranged todrive said web over the web contacting surface thereof;

first and second bearing mounting means having a spherical portionattached to said driving means along a common axis on opposite sidesthereof and a second spherical portion attached to said main frame forforming self-aligning bearings therebetween; and

a third bearing mounting means having a spherical portion attached tosaid mounting plate means perpendicular to said common axis, formed bysaid first and second bearing mounting means, and a second sphericalportion attached to said main frame for forming a self-aligning bearingtherebetween;

whereby said mounting plate means is free from stress caused bymovements of said main frame.

6. A mounting arrangement as claimed in claim 5, wherein:

said first, second, and third bearing mounting means are arranged toform a plane which passes through the center of gravity of said mountingarrangement;

said third bearing mounting means is arranged at the center ofpercussion of said mounting arrangement;

whereby vibrational forces parallel to said web contacting surface areprevented from deflecting said surface and vibrational forcesperpendicular to said web contacting surface produces a rotational forceabout said common axis formed by said first and second bearing means. 7.A mounting arrangement as claimed'in claim 5, additionally comprising:

enclosure means extending from said web contacting surface;

8. A mounting arrangement as claimed in claim 6, wherein said web ismagnetic tape, and said driving means includes a capstan and capstanmotor means.

1. A mounting arrangement for isolating a vibration sensitive assemblyfrom shock and vibration and the stress caused thereby, comprising: amain frame; a vibration sensitive assembly; mounting plate means forsupporting said vibration sensitive assembly; first, second, and thirdmounting means each connected between said main frame and said mountingplate means and arranged to allow a movement of said mounting platemeans in all planes with respect to said main frame; said first, second,and third mounting means each having one axis of movement arranged in aplane passing through the center of gravity of the combination of saidmounting plate means and said vibration sensitive assembly; and wherebysaid vibration sensitive assembly is isolated from stress created bymovements of said main frame.
 2. A mounting arrangement as claimed inclaim 1, wherein said mounting means include bearing means having aspherical portion attached to said mounting plate means and a secondspherical portion arranged to receive said first mentioned sphericalportion attached to said main frame.
 3. A mounting arrangement asclaimed in claim 1, wherein: said vibration sensitive means includes aweb driving means and a surface parallel to a driven web; and wherebyvibrational forces parallel to said surface are prevented fromdeflecting said surface.
 4. A mounting arrangement as claimed in claim1, wherein: said first and second mounting means attach to said mountingplate means and extend oppositely therefrom along a common axis forattachment to said main frame; said third mounting means attaches tosaid mounting plate means and extends therefrom perpendicularly to thecommon axis formed by the first and second mounting means at the centerof percussion of the combination of said mounting plate means and saidvibration sensitive assembly for attachment to said main frame; saidvibration sensitive assembly includes a web driving means and a surfaceparallel to a driven web; and whereby vibrational forces perpendicularto said surface produce a rotational force about said common axis formedby said first and second mounting means.
 5. A mounting arrangement forisolating a web driving assembly from shock and vibration and the stressCaused thereby, comprising: a main support frame; mounting plate meanshaving a web contacting surface; driving means mounted upon saidmounting plate means and arranged to drive said web over the webcontacting surface thereof; first and second bearing mounting meanshaving a spherical portion attached to said driving means along a commonaxis on opposite sides thereof and a second spherical portion attachedto said main frame for forming self-aligning bearings therebetween; anda third bearing mounting means having a spherical portion attached tosaid mounting plate means perpendicular to said common axis, formed bysaid first and second bearing mounting means, and a second sphericalportion attached to said main frame for forming a self-aligning bearingtherebetween; whereby said mounting plate means is free from stresscaused by movements of said main frame.
 6. A mounting arrangement asclaimed in claim 5, wherein: said first, second, and third bearingmounting means are arranged to form a plane which passes through thecenter of gravity of said mounting arrangement; said third bearingmounting means is arranged at the center of percussion of said mountingarrangement; whereby vibrational forces parallel to said web contactingsurface are prevented from deflecting said surface and vibrationalforces perpendicular to said web contacting surface produces arotational force about said common axis formed by said first and secondbearing means.
 7. A mounting arrangement as claimed in claim 5,additionally comprising: enclosure means extending from said webcontacting surface; cover means contacting said enclosure means forforming bin means into which said web is driven by said driving means;and whereby said web is edge guided by said web contacting surface andsaid cover means.
 8. A mounting arrangement as claimed in claim 6,wherein said web is magnetic tape, and said driving means includes acapstan and capstan motor means.